My 1965 Tradewind has 1/2 in plywood floor is it unique? I know this to be
true because I replaced the bath floor. As far as the descussion about exterior
ply versis marine I will speak from many years around boats buth building and
repairing.All untreated fir plywood will rot with equal speed if it is not
protected from moisture pinitration, the untreated edges will wick up moisrure
and siowly rot. as far as streangth marine ply is stronger.and for the perpose
that we are using it for voids are not a provlem.
Years ago I used to race outboard hydroplanes at speeds aproching 100 mph I
used to use expencive imported marine ply and later switched to using exterior
ply for these boats never had one brake apart when raceing eaven in rough
water. used 1/4 in 3 ply for the bottom and treated door skins for the decks.many
of us on a budget went this route I have seen many river skiffs bult from A-C
fir ply and depending on the care given they lasted a good long time. the
biggest contributing factor to wood rot is wetting and drying out and having the
process repeted over ans over.
Jim smith